The present invention relates to a substrate with a check-land, which is fixed to a housing holding an optical element, and a check-land connecting device used for an electrical connection to a check-land of a substrate with a check-land.
A substrate with a check-land of the above described type is well-known. The check-land is used to check an electrical circuit as to whether it can normally operate or not after the electrical circuit is structured on a substrate in a manufacturing process of an electric circuit board, or to check an apparatus using an electric circuit board as to whether the apparatus can operate normally or not when the electric circuit board is mounted on the apparatus. Further, the check-land is used to measure an output of a photo detector, which includes optical elements, so as to adjust the optical elements and check an erroneous displacement of an optical axis of any one of the optical elements.
The above described checking operation is carried out by bringing a probe of a test device into contact with the check-land. The probe functions as a check-land connecting device used to electrically connect the test device to the check-land.
When the probe of the test device is brought into contact with the check-land, a pressure force of about several tens of grams per one probe is applied on the respective check-land to ensure an electrical connection between them, and therefore the substrate is warped. If the substrate is warped, a housing to which the substrate is fixed is accordingly warped. In this case, where the housing holds an optical element, the warping of the housing may cause a warping of the optical element or cause an erroneous displacement of an optical axis. However, if the pressure force applied to the probe is reduced to avoid the warping of the substrate, the electrical connection becomes unstable so that errors contained in measured electrical signals or optical characteristics becomes large. Therefore, in a case where a housing to which a substrate with a check-land is fixed, holds an optical element, a checking operation using the check-land must be carried out very carefully. Consequently, the checking operation requires relatively much time.
The present invention has been derived from the above-described circumstances, and an object of the present invention is to provide a substrate with a check-land, which can perform a checking operation via the check-land easily and accurately in a short time, even in a case where a housing to which the substrate with a check-land, holds an optical element.
Another object of the present invention is to provide a check-land connecting device which is suitable to be used for an electrical connection to the check-land of the substrate with a check-land, the substrate having the above-described structure according to the present invention.
In order to achieve the above described object of the present invention, a substrate with a check-land according to the present invention, is fixed to a housing holding an optical element, and has a checkland, a portion of the substrate, which includes the check-land, has a flexibility with respect to the other portion which does not include the check-land.
With the substrate with the check-land according to the present invention and having the above-described structure, when pressing the check-land with a probe of a test device, it is possible to place an opposite surface of the check-land portion on a receiving table, the opposite surface facing in a direction opposite to a direction in which the check land faces. Then, the probe can be pressed onto the check-land at a desired pressure force necessary to perform a checking operation while the check-land portion of the substrate with the check-land is placed on the receiving table.
Even if the portion of the substrate, which includes the check-land, is warped with respect to the other portion which does not include the check-land due to a pressure generated by the placement of the check-land portion on the receiving table and a pressure applied from the probe, such warping of the check-land portion of the substrate is not propagated to the other portion due to a flexibility of the check-land portion.
Consequently, the substrate is not warped by the above described desired pressure force applied to the check-land via the probe, and therefore the housing to which the substrate is fixed does not warp. In the case where the housing holds the optical element, the warping of the optical element or the erroneous displacement of the optical axis of the optical element, which is caused by the warping of the housing, does not occur.
Further, since the probe is pressed on the check-land at the above described desired pressure force, the electrical connection between them can be assured, and therefore it is possible not to generate errors in measured electrical signals or optical characteristics.
Therefore, even in the case where the housing to which the substrate with the check-land is fixed, holds the optical element, the checking operation using the check-land can be performed easily and accurately within a short time.
In the substrate with a check-land, having the above-described structure and according to the present invention, the housing may hold optical elements including a laser light source and a solid immersion lens, and may be used to record information on a recording layer of an optical disk and to reproduce information from the recording layer, by applying a laser beam from the laser light source to the recording layer of the optical disk via the solid immersion lens.
It is preferable that the substrate with a check-land, having the above-described structure and according to the present invention, includes a flexible substrate and a reinforcing plate attached to the flexible substrate, and the check-land is arranged in a portion of the flexible substrate, which does not correspond to the reinforcing plate.
In the above-described structure, even in the case where the reinforcing plate is attached to the flexible substrate to protect circuit wirings formed on the flexible substrate, the checking operation using the check-land can be performed easily and accurately within a short time.
In the substrate with a check-land, having the above-described structure and according to the present invention, it is preferable that the portion which includes the check-land is formed to project from the other portion which does not include the check-land.
Such a substrate with a check-land is simple in its structure.
In the substrate with a check-land, having the above-described structure and according to the present invention, it is preferable that the portion which includes the check-land is formed integral with the other portion which does not include the check-land.
Such a substrate with a check-land is a simple in its structure.
In the substrate with a check-land, having the above-described structure and according to the present invention, the portion which includes the check-land may have a connection region connecting a region surrounding the check-land to the other portion which does not include the check-land, and outer dimensions of the connection region can be made smaller than outer dimensions of the region surrounding the check-land.
In the substrate with a check-land, having the above-described structure and according to the present invention, the portion which includes the check-land can be partially separated by a slit from the other portion which does not include the check-land.
In order to achieve the above-described object of the present invention, it is preferable that the check-land connecting device used for electrical connection to a check-land of a substrate with a check-land, includes: a probe used to be pressed on the check-land of the substrate with the check-land; and a base member used to be abutted to a region of a rear surface of the substrate with the check-land, the region of the rear surface being opposed to the check-land but corresponding to the check-land, wherein the probe and the base member are connected to be mutually approachable and separatable.
Additional objects and advantages of the invention will be set forth in the specification which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized by means of the instrumentalities and combinations particularly pointed out hereinafter.